Process for plating metals.



CLARK W. PARKER, OF DETROIT,

MICHIGAN, ASSIGNOR TO PARKER RUST PROOF COMPANY OF AMERICA, OF DETROIT,MICHIGAN, A CORPORATION OF'MICHIGAN.

PROCESS FORJPLATING METALS.

No Drawing.

To all whom it may concern:

Be it known that I, CLARK W. PARKEn, a citizen of the United States, andresiding at Detroit, in the county of Wayne and State of Michigan, haveinvented a new and Improved Process for ,Plating Metals, of which thefollowing is a specification.

This invention relates to the electro-plating of articles of iron andsteel and 'its 0b ject is. to reduce the number of operations and tocheapen the cost of such work.

This invention consists in first treating the finished surfaces of thearticles of iron and steel by immersing them in a hot solution ofphosphoric acid, then placing the articles thus treated in an ordinaryelectroplating bath, and finally buffing the articles if a polish isdesired.

It also consists in adding manganese oxid to the solution of phosphoricacid in order to intensify the action of the acid.

It further consists in scratch-brushing or buffing the surfaces afterthe acid treatment in order to obtain a fine smooth surface on which todeposit the nickel or other coating metal.

In the electro-plating of steel with nickel, the surfaces are firstfinished, then greased and buffed, then dipped in a solution of potash,and then in hot water, then brushed with pumice and dipped in coldwater, then plated with copper, then bufi'ed, then again dipped in apotash solution and in hot water, again brushed with pumice and dippedin cold water and then nickel plated.

In the present process,the surfaces are first finished, then treatedwith a weak solution of phosphoric acid, and then are immediately platedwith nickel, brass or any other desired metal. The action of thephosphoric acid is to change the surface of. iron or steel to adull-black phosphate the of iron which will readily receive and retainthe deposit of coating metal.

For some reason not now understood, a much hi her voltage may be used innickel plating articles thus treated than is permissible with ordinarypractice, as theburning of the edges of the articles being plated whichis common with high voltage under ordinaryconditions, is entirelylacking. The time required .to deposit a given coat of metal istherefore greatly reduced.

I Specification of Letters Patent.

Patented Jan. 2, 1917.

Application filed July 31, 191G. Serial No. 112,250.

To produce a smooth surface, the articles taken from the phosphoric acidbath may be cleaned and smoothed with a metal brush .or by brushing withemery or pumice. For

nickel plating on a surface thus prepared,

, a nickel sulfate solution has been found desirable. The acid bathisprepared by. placing three pounds of manganese dioxid in a solution ofone-halfgallon of phosphoric acid in substantially one hundred gallonsof water and then bringing the bath to practically the boiling point .atwhich temperature it is most effective. As bubbles of hydrogen gasescape from the articles being treated it is possible that galvanicaction takes place and that a film of ferric phosphate is deposited onthe articles being treated. When the bubbles stop forming, this step inthe process is completed.

While this process is especially adapted for nickel plating because itsaves the preliminary step of copper plating, copper, brass and silversolutions may be substituted for the nickel solution and good re- Isults obtained.

I claim l. The process of metal-coating articles of iron and steel whichconsists in immersing them in a heated solution of phosphoric acid andthen suspending them in an electroplating bath.

2. The process of coating articles of iron and steel with another metalwhich con- .sists in immersing the same in a bath containing a solutionof phosphoric acid and then suspending them in an electro-plating bathembodying a soluble compound of the metal to be deposited.

3. The process of coating articles of iron and steel with nickel whichconsists in immersing the same in a heated bath containing a solution ofphosphoric acid and an intensifying agent and then suspending the same1n an electro-plating bath embodying 1 a solution of nickel sulfate.

4.. The process of coating articles of iron and steel with nickel whichconsists in immersing the same in a heated solution of phosphoric acidand manganese oxid, then mechanically cleaning the surfaces, and thensuspending the same in a nickel plating bath.

CLARK W. PARKER.

